In short,there are three pieces of basic equipment for skin diving.The face mask covers the eyes and nose. It allows the diver to see clearly under water.Remember,the mask must provide aleakproof seal.Test the mask before you buy it.The snorkel is the breathing tube.It should fit comfortably in the month.Finally,the flexible fins give the diver added swimming propulsion.There are two kinds the open-heel fin and the slipper fin.